There is no ready-made answer to this question. Both are possible, it will depend on your expectations.
If the sunscreen is the final step in your morning skincare routine, the skin fully benefits from the active ingredients contained in the tinted serum, then the sunscreen forms a protective barrier against the harmful effects of UV rays. However, it may leave a slight white finish on the surface of the skin.
However, if you truly desire a "make-up" finish with smooth and very even skin, you can apply your sunscreen before your tinted moisturizer. On the other hand, the benefits that the tinted moisturizer can provide to the skin will be lessened. Indeed, the sunscreen, forming a barrier on the surface of the epidermis, inhibits the deep penetration of active ingredients.
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